This invention relates to an ultraviolet light absorber composition which is readily diluted in, and applied from, a water-based textile dye bath to improve the lightfastness, or fade-resistance, of a dyed textile material, for example, knitted or woven fabric. The invention is based upon the synergistic combination of a UV light absorber and a suitable solvent. When using a water immiscible solvent, a solvent-soluble emulsifier (surfactant) is added such that the resulting composition spontaneously forms an emulsion when diluted in water. The emulsifier may also be applicable when using a water miscible solvent to improve the dilutability of the UV light absorber. The water miscible solvent dissolves in the water-based dye bath to form an extremely fine dispersion of UV light absorber.
The dyed textiles treatable by this invention generally include synthetic fibers, such as polyester and nylon (polyamide). According to one application, the invention is applied to disperse-dyed polyester fabric used in automobile interiors, for example, in seat upholstery, door and head liners, and carpeting, to improve the fade-resistance of the fabric.
In order to apply UV light absorbers and other light stabilizers to textiles after the textile fiber has been formed rather than in the melt-extrusion stage, the absorber/stabilizer agents must be dilutable in water to be effectively used in conventional textile dyeing and processing machinery. Standard UV light absorber and light stabilizer compounds, however, have little or no solubility in water, and must therefore be wet-milled. Wet-milling is a process of mechanically, grinding down the absorber/stabilizer agents in water in small media mills, e.g., sand mills or ball mills, together with various dispersing and wetting agents, processing aids, and the like. Other ingredients such as leveling agents, particle recrystallization inhibitors, preservatives, defoamers, and thickeners are also generally required.
Although reasonably effective, the wet-mill process suffers from numerous drawbacks and limitations. A great deal of time and energy is required to physically break down the absorber/stabilizer agents. Typically, the particle size must be less than two microns mean diameter in order to produce a suitable aqueous dispersion that is both storage stable, and will not filter out when passed through many layers of fiber or fabric in conventional dyeing machinery, such as in package or beam dyeing machines. The wet-mill process may take as long as several days for a single preparation.
Therefore, it is an object of the invention to provide a UV light absorber composition which spontaneously dilutes in a water-based dye bath.
It is another object of the invention to provide a UV light absorber composition which is easily made in a relatively short timexe2x80x94within minutes to a couple of hours.
It is another object of the invention to provide a UV light absorber composition which does not require the use of expensive capital equipment, such as sand mills or ball mills.
It is another object of the invention to provide a UV light absorber composition which requires minimal energy to producexe2x80x94for example, simple mixing at room temperature.
It is another object of the invention to provide a UV light absorber composition which is storage stable, and thus will not settle out or recrystallize over time as in wet-milled dispersions.
It is another object of the invention to provide a UV light absorber composition which is non-aqueous, and thus will not support the growth of microorganisms, such as mold, fungus, and bacteria.
It is another object of the invention to provide a method of improving the lightfastness of dyed textiles.
These and other objects of the present invention are achieved in the preferred embodiments disclosed below by providing a UV light absorber composition for improving the lightfastness of dyed textiles. The composition includes from about 5-75% by weight of an ultraviolet light absorbing agent selected from the group consisting of benzotriazole, benzophenone, and phenol substituted triazine; and from about 25-95% by weight of an organic solvent suitable for dissolving the ultraviolet light absorbing agent. The ultraviolet light absorbing agent is applied to the textiles in a concentration sufficient to result in an add-on in the range of between 0.4-4.0% by weight of the textiles when dry.
According to one preferred embodiment of the invention, the organic solvent is a water miscible solvent.
According to another preferred embodiment of the invention, the organic solvent is a water immiscible solvent, and the composition further includes from about 2-25% by weight of a surfactant.
Preferably, the surfactant is nonylphenoxy-polypropyleneoxy-polyethyleneoxy-ethanol.
According to another preferred embodiment of the invention, the composition includes from about 2-25% by weight of a surfactant in a water miscible solvent.
According to yet another preferred embodiment of the invention, the composition includes an additional light stabilizer selected from the group including hindered amines and organo-copper complexes.
According to yet another preferred embodiment of the invention, the composition includes an anti-oxidant.
Preferably, the UV light absorbing agent is 2-(2-hydroxy-5-tert-octylphenyl)-benzotriazole.
Preferably, the organic solvent is N-methyl-pyrrolidone.
Preferably, the ultraviolet light absorbing agent is applied to the textiles in a concentration sufficient to result in an add-on of approximately 1.0% by weight of the textiles when dry.
According to one preferred embodiment of the invention, a UV light absorber composition for improving the lightfastness of dyed textiles includes from about 10-30% by weight of 2-(2-hydroxy-5-tert-octylphenyl)-benzotriazole, from about 55-85% by weight of N-methyl-pyrrolidone solvent, and from about 5-15% by weight of nonylphenoxy-polypropyleneoxy-polyethyleneoxy-ethanol. The benzotriazole is applied to the textiles in a concentration sufficient to result in an add-on in the range of between 0.4-4.0% by weight of the textiles when dry.
An embodiment of the method according to the invention comprises the steps of formulating a UV light absorbing composition. The composition includes from about 5-75% by weight of an ultraviolet light absorbing agent selected from the group consisting of benzotriazole, benzophenone, and phenol substituted triazine; and from about 25-95% by weight of an organic solvent suitable for dissolving the ultraviolet light absorbing agent. The ultraviolet light absorbing agent is applied to the textiles in a concentration sufficient to result in an add-on in the range of between 0.4-4.0% by weight of the textiles when dry. The method further includes adding the above composition and textiles to be treated into a water-based dye bath.
According to one preferred embodiment of the invention, the method includes the step of scouring the textiles with a scouring agent prior to adding the textiles to the water-based dye bath.
According to another preferred embodiment of the invention, the method includes the step of heating the textiles after scouring to a temperature in the range of about 60xc2x0 C. to about 80xc2x0 C. at a rate of 2xc2x0 C. per minute, and prior to adding the textiles to the dye bath.
According to yet another preferred embodiment of the invention, the method includes the step of drying the textiles prior to adding the textiles to the dye bath.
According to yet another preferred embodiment of the invention, the step of formulating a UV light absorbing composition includes the step of adjusting the pH of the composition to between about 4.0 and 5.0 prior to adding the composition to the dye bath.
Preferably, the step of formulating a UV light absorbing composition includes the step of adjusting the pH of the composition to about 4.8 prior to adding the composition to the dye bath.
The UV light absorber composition of the present invention is a non-aqueous composition usable in water-based dye baths for enhancing the lightfastness of dyed textiles. The composition includes a mixture of at least a UV light absorbing agent and a suitable solvent. For a water immiscible or partially immiscible solvent, the composition further includes an emulsifier such that the composition spontaneously forms an emulsion when diluted in water. An emulsifier may also be used with water miscible solvents to improve the dilutability of the composition in the dye bath.
The UV light absorbing agent is chosen from one or more of the following classes; benzotriazole, benzophenone, and phenol substituted triazine. Preferably, these agents are used individually, but may be used in combination to obtain various mixtures of active UV light absorbing ingredients. One preferred benzotriazole UV light absorbing agent is 2-(2-Hydroxy-5-tert-octylphenyl)-benzotriazole, CAS Reg. No. 3147-75-9, which is commercially available as xe2x80x9cCyasorb UV-5411xe2x80x9d from Cytec Industries. Examples of suitable benzophenones and phenol substituted triazines are disclosed in U.S. Pat. Nos. 4,826,978 and 4,964,871. A number of other commercially available UV light absorbing agents are set forth in the Examples provided below.
The solvent may be any suitable water miscible or immiscible organic solution, or mixture of water miscible and immiscible solutions, capable of dissolving the active UV light absorbing agent of the composition. For compositions using a water immiscible or partially immiscible solvent, the solvent must further be capable of dissolving the added emulsifier. A number of applicable solvents are provided in the Examples below. In addition, for water insoluble dyes, such as disperse dyes, the solvent can function as a carrier or diffusion accelerator for the UV light absorbing agent into hydrophobic fibers, such as polyester. Solvents chosen from the class of plasticizer esters are especially suitable for this purpose.
The emulsifier is preferably chosen from the group including alkanolamides, ethylene oxide/propylene oxide block polymers, alkylphenol ethoxylates, dialkylphenol ethoxylates, styrenated-phenol ethoxylates, ethoxylated alcohols, ethoxylated fatty acids (esters), ethoxylated amines, ethoxylated amides, glycerol esters, ethoxylated glycerol esters, sorbitan esters, ethoxylated sorbitan esters, sucrose and glucose esters, alkyl polyglycosides, ethoxylated alkyl thiols, ethoxylated thio-ethers. Wherever the terms xe2x80x9cethoxylatedxe2x80x9d or xe2x80x9cethoxylatesxe2x80x9d are used, the ethoxylated/propoxylated variations could also be used. A listing of suitable commercially available emulsifiers is provided in McCutcheon""s Emulsifiers and Detergents 1994xe2x80x94North American and International Editions (McCutcheon Division, MC Publishing, 175 Rock Road, Glen Rock, N.J. 07452).
For applicability to the present UV light absorbing composition, the emulsifier selected must be soluble in the particular water miscible or immiscible solvent used. Generally, to be soluble in such solvents, the hydrophilic-lipophilic balance (HLB) of the emulsifier should be less than about 13. The most preferred nonionic emulsifiers should have HLBs of about 5 to 11.
In addition, certain ionic emulsifiers may be used in the present composition, provided they are sufficiently soluble in the solvent. However, because many dye baths typically contain anionic dispersants, the ionic emulsifier used should also be anionic or possibly amphoteric. Cationic emulsifiers may not be compatible in the final dye baths where the UV light absorbing composition would commonly be applied.
According to one preferred embodiment, the UV light absorber composition includes approximately 5-75% of organic UV light absorbing agent; approximately 25-95% of organic solvent; and for water immiscible or partially immiscible solvents, approximately 2-25% of an emulsifier which is soluble in the above mixture. The solvent must therefore be capable of dissolving at least 5% of a UV light absorbing agent, and at least 2% of an emulsifier when applicable.
In alternative embodiments, the UV light absorbing agent of the composition is combined with other classes of light stabilizers, such as hindered amines and organo-copper complexes; and/or various anti-oxidant compounds to achieve synergistic lightfastness and fiber protection effects. One suitable hindered amine is Bis(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate, commercially available as xe2x80x9cTinuvin 292xe2x80x9d from Ciba-Geigy. Examples of suitable organo-copper complexes are described in U.S. Pat. Nos. 4,990,164 and 5,076,808. One suitable anti-oxidant compound is xe2x80x9cCyanox 2777xe2x80x9d from Cytec Industries.
The present UV light absorbing composition is applicable in beam and package dyeing of textiles, and dyeing operations where the dye bath liquor is stationary and the fabric is moving, such as in jet dyeing and continuous dyeing machines.